This invention relates to universal lever apparatus having an operation lever pivotally movable in two directions, and more particularly to a universal lever apparatus in which lock means is provided for locking the operation lever to keep same from pivotally moving in the two directions.
Hydraulic construction machines, such as hydraulic excavators, usually have a pair of universal lever apparatus located near the right and left sides of a drivers seat in a cab, and each universal lever apparatus is manipulated by the driver for operating working elements such as a swing, travel members, etc.
One type of universal lever apparatus known in the art comprises an operation lever pivotally movable in a first direction and a second direction, a first rod connected to the operation lever for movement to actuate an operated member as the operation lever moves in the first direction, and a second rod connected to the operation lever for movement to actuate another operated member as the operation lever moves in the second direction. The operated member actuated by the first rod may be an operated section of a directional control valve for hydraulically driving a working element, and the operated member actuated by the second rod may be an operated section of another directional control valve for hydraulically driving another working element. Thus, the driver can operate two working elements by manipulating the operation lever of one of the pair of universal lever apparatus.
The aforesaid type of universal lever apparatuses have hitherto been usually located in front of the right and left sides of the driver's seat in a position in which the operation lever of each universal lever apparatus does not interfere with the movement of the driver in entering or leaving the cab.
Proposals have in recent years been made to arrange the universal lever apparatuses of the aforesaid type in a position adjacent to the right and left sides of the driver's seat. When the universal lever apparatuses are arranged in such a position, the operation levers of universal lever apparatuses will be located sideways of the driver's seat. If the operation levers are located in this position, one of them would interfere with the movement of the driver in entering and leaving the cab, making it impossible for the driver to act nimbly. An additional disadvantage would be that if the hand or body of the driver were inadvertently brought into contact with the operation lever, there would be the risk that the operation lever might be actuated by mistake, raising a problem with regard to the safety of operation.
Japanese Utility Model Laid-Open No. 68331/79 discloses a universal lever apparatus of the aforesaid type which is provided with a lock mechanism for locking the operation lever in a neutral position to keep same from pivotally moving in two directions. The provision of this lock mechanism would have the effect of avoiding unintentional movement of the operation lever even if the driver touches the operation lever when entering or leaving the cab. However, this lock mechanism is intended merely to lock the operation lever in its neutral position and does not essentially provide a solution to the problem that the operation lever interferes with the movement of the driver and prevents him from acting nimbly when he enters or leaves the cab.
Additionally the lock mechanism is not adapted to prevent the driver from forgetting to lock the operation lever before leaving the cab, and therefore the operation lever might be moved by mistake when the driver enters or leaves the cab.